/* object */
'use strict'

var Lucca = {
    name: 'Lucca',
    birth: 2000,
    school: 'BIT',
    height: 1.73,
    weight: 85,
    score: null
};

Lucca.name;

var xiaohong = {
    'name': "小红",
    'middle-school': 'BIT'
};

xiaohong['middle-school'];
xiaohong['name'];

Lucca = {
    name: 'Lucca'
};

Lucca.age;  // < undefined
Lucca.age = 18;
Lucca.age;  // < 18

delete Lucca.age;   // < true
Lucca.age;  // < undefined

delete Lucca[name]; // < true
Lucca.name; // < undefined

delete Lucca.school;    // < true
// 删除不存在的属性也不会报错

// 注意要加引号
'name' in Lucca;                // < true
'non-exist-property' in Lucca;  // < false

'toString' in Lucca;    // < true

Lucca.hasOwnProperty('name');       // < true
Lucca.hasOwnProperty('toString');   // < false